132 



THE AMOEBAE 



produced ulcers in the nasal mucous mem- 

 brane and invaded the adjacent base of the 

 skull, involving the frontal lobes of the 

 brain and causing death in about 4 days. 

 Following intravenous inoculation into 

 mice, they caused perivascular granulo- 

 matous lesions in the lungs. These were 

 associated with severe pneumonia, exten- 

 sive fibrinopurulent exudate containing 

 polymorphonuclear leucocytes and mono- 

 cytes, hemorrhage, and invasion of the 

 pulmonary veins followed by the formation 

 of thrombi containing the amoebae. 



McCowen and Galloway (1959) also 

 isolated Acanlhamoeba sp. from tissue 

 cultures of trypsinized monkey kidney 

 cells. They studied the pathogenicity for 

 mice of this strain and of others isolated 

 from the same source. The average sur- 

 vival time of intracerebrally inoculated 

 mice was approximately 5 days. Cysts 

 remained virulent for mice after storage 

 at -67 °C for 15 months. 



Genus SAPPINIA Dangeard, 1896 



In this genus the trophozoites have 2 

 closely associated nuclei with large endo- 

 somes. The cysts are binucleate also. 



Sappinia diploidea (Hartmann and 

 Nagler, 1908) Alexeieff, 1912 is a com- 

 mon coprophilic amoeba in the feces of 

 man and other animals. Its trophozoites 

 are 10 to 60 fi long, with a thick, smooth, 

 hyaline pellicle; according to Noble (1958), 

 the ectoplasm has fine lines sometimes 

 resembling wrinkles in cellophane. Two 

 nuclei are present, usually pressed 

 tightly together. Each nucleus has a 

 large endosome and frequently a crescentic 

 mass of granules between the endosome 

 and the nuclear membrane. The cytoplasm 

 is usually filled with many food vacuoles. 

 A contractile vacuole is present, formed 

 by the enlargement and coalescence of 

 smaller vacuoles. A single, clear, broad 

 pseudopod is characteristic, altho occa- 

 sionally many pseudopods may be present. 

 Cytoplasmic granules and food vacuoles 

 are concentrated between the pseudopod 

 and the rest of the body. Movement is 

 quite sluggish. The cytoplasmic granules 



usually move rapidly. The cysts are typ- 

 ically binucleate, 12 to 18/i or more in 

 diameter, with thick, uniform walls. The 

 cysts are formed from 2 individuals which 

 come together and secrete a common cyst 

 wall; their nuclei fuse so that each one has 

 a single nucleus, their cytoplasm fuses, 

 each nucleus gives off reduction bodies, 

 and the 2 remaining nuclei come into con- 

 tact to make the cyst binucleate. 



Noble (1958) found that 6'. diploidea 

 appeared in fecal samples from Wyoming 

 elk and bison (but not from cattle, horses 

 and sheep) after storage at 4° C for a few 

 days to a few weeks. It failed to survive 

 in soil or in soil mixed with boiled feces, 

 nor could it be found in soil samples taken 

 from areas where elk, sheep or horses 

 were present. 



S. diploidea is readily cultivated. 

 Noble (1958), for example, cultivated it 

 both at 4^^ C and at room temperature on 

 the surface of agar plates containing 1. 5% 

 agar, 0. 05% yeast extract and 0. 05% pep- 

 tone. The cultures held at room temper- 

 ature became moldy after 6 weeks. Sap- 

 pinia was present for 2 to 3 weeks in the 

 cultures at 4° C. 



Genus VAHLK4MPF/A Chatton and 



Lalung-Bonnaire, 1912 emend. 



Calkins, 1913 



These are small amoebae with a nu- 

 cleus containing a large endosome and 

 peripheral chromatin, with polar caps 

 during nuclear division. The trophozoites 

 have a single broad pseudopod and move 

 like a slug. The cysts have a perforated 

 wall. The nucleus of this genus closely 

 resembles that of Naegleria, but the latter 

 has both flagellate and amoeboid stages. 

 A number of species have been described 

 from fresh water, old feces, lower verte- 

 brates and invertebrates, but the taxonomy, 

 nomenclature and validity of some of them 

 are not certain. 



Vahlkampfia punctata (Dangeard, 1910) 

 Chatton and Lalung-Bonnaire, 1912 has 

 been found in human feces. Its cysts have 

 punctate markings. 



